Malignant melanoma, breast cancer and lung cancer are the most causative malignancies of leptomeningeal carsinomatosis (LC). A LC case that was previously diagnosed as tuberculosis meningitis, is presented here to emphasize the importance of maintaining a broad differential diagnosis in patients applied to the hospital with meningeal irritation symptoms. A 35-year-old woman was suffering from a severe headache and photophobia. Physical examination revealed nuchal rigidity but Kernig’s and Brudzinski signs were negative. Cerebrospinal fluid (CSF) findings were 171 cells/mm3 (lymphocytic predominance), elevated protein levels, decreased glucose. Atypical cells were detected in CSF cytology. The result of breast biopsy was in accordance with breast lobular carcinoma nuclear grade III. LC, usually developes in patients who have a known primary malignancy. As it occured in our case; in up to 10%-20% of cases, however, symptoms caused by LC may emerge before the diagnosis of the primary tumor. It should remember that meningitis may not be always infectious originated. J Microbiol Infect Dis 2015;5(3): 133-136 Key words: leptomeningeal carcinomatosis, meningitis, cerebrospinal fluid cytology